Florfenicol, also known as 2,2-dichloro-N-[(1S,2R)-1-(fluoromethyl)-2-hydroxy-2-[4-(methylsulfonyl)phenyl]ethyl}-acetamide or [R—(R*,S*)]-2,2-Dichloro-N-[1-(fluoromethyl)-2-hydroxy-2-[4-(methylsulfonyl)phenyl]ethyl]acetamide, is a broad spectrum antibiotic of Formula I. Florfenicol is a structural analog of thiamphenicol, which in turn is a derivative of chloramphenicol [see, e.g., U.S. Pat. No. 4,235,892, U.S. Pat. No. 5,352,832, the contents of which are hereby incorporated by reference in their entireties].

Florfenicol has broad spectrum antibiotic activity against many gram-negative and gram-positive bacteria, including utility in the prevention and treatment of bacterial infections due to susceptible pathogens in birds, reptiles, fish, shellfish and mammals. One of florfenicol's primary uses is in the treatment of pneumonia and associated respiratory infections in cattle (often referred to generically as Bovine Respiratory Disease or BRD) caused by Mannhemia haemolytica, Pasturella multocida and/or Haemophilus somnus, also known as Histophilus somni. It is also indicated in the treatment of: pododermatitis in cattle caused by Fusobacterium necrophorum and Bacterioides melaminogenicus; swine respiratory disease caused by Pasteurella multocida, Actinobacillus pleuropneumoniae, Streptococcus suis, Salmonella cholerasuis and/or Mycoplasma spp.; colibacillosis in chickens caused by Escherichia coli; enteric septicemia in catfish caused by Edwardsiella ictaluri; and furunculosis in salmon caused by Aeromonas salmonicida. Other genera of bacteria that have exhibited susceptibility to florfenicol include Enterobacter, Klebsiella, Staphylococcus, Enterococcus, Bordetella, Proteus and Shigella. In particular, chloramphenicol-resistant strains of organisms, such as K. pneumoniae, E. cloacae, S. typhus and E. coli, are susceptible to florfenicol.
Florfenicol is used in veterinary medicine where the cost of goods is a major factor for the consumer. It is therefore important to have chemically efficient and economical processes for its manufacture. Such processes assure that this important antibiotic is available to the consumer at a competitive price.
The citation of any reference herein should not be construed as an admission that such reference is available as “Prior Art” to the instant application.